Subacute sclerosing panencephalitis: measles encephalitis of temperate evolution?

Subacute sclerosing panencephalitis is a rare disorder of late childhood and early adolescence Affected patients usually show behavioural and intellectual disturbance and involuntary movements before dying in coma after about 12 months. At some stage most have characteristic electroencephalographic abnormalities. Pathologically, changes in the brain are those of subacute encephalitis with a variable gliosis of the white matter, and sometimes intranuclear inclusion bodies in neurones and glial cells. Recent studies in many patients have shown high levels of circulating anti-measles antibodies, measles antigen in cells in the brain, and sometimes, myxo-virus filaments in cells there. These findings suggest that SSPE may be a slow measles virus infection of the nervous system. Possible explanations for the slow evolution of the encephalitis include disordered immune mechanisms and intracellular persistence of virus in a defective phase.